Gas circuit breaker

A gas circuit breaker, comprising:

• a first arc contactor electrically connected to a first lead-out conductor connected to a power system;
• a cylindrical guide portion provided at a second lead-out conductor side;
• a trigger electrode which is arranged to be movable between the first arc contactor and the guide portion, and which ignites an arc generated between the first arc contactor and the trigger electrode along with a movement in a first half of a current breaking action;
• a compression chamber for pressurizing arc-extinguishing gas, the compression chamber being formed by a cylinder which has an outer wall and an inner wall both formed in a cylindrical shape and which is provided on the guide portion side, and a piston which slides between the outer wall and the inner wall in conjunction with the trigger electrode;
• and
• an insulation nozzle which guides the arc-extinguishing gas pressurized in the compression chamber to an arc ignited at the first arc contactor,
• wherein:
• the insulation nozzle is formed integrally with the inner wall of the cylinder, and
• the cylinder includes a check valve which closes between the compression chamber and the pressure accumulating path which guides, to the arc, the arc-extinguishing gas pressurized in the compression chamber, when a pressure of the arc-extinguishing gas in the compression chamber is equal to or larger than a predetermined value.

A gas circuit breaker, comprising:

• a first arc contactor electrically connected to a first lead-out conductor connected to a power system;
• a cylindrical guide portion provided at a second lead-out conductor side;
• a trigger electrode which is arranged to be movable between the first arc contactor and the guide portion, and which ignites an arc generated between the first arc contactor and the trigger electrode along with a movement in a first half of a current breaking action;
• a compression chamber for pressurizing arc-extinguishing gas, the compression chamber being formed by a cylinder which has an outer wall and an inner wall both formed in a cylindrical shape and which is provided on the guide portion side, and a piston which slides between the outer wall and the inner wall in conjunction with the trigger electrode;
• and
• an insulation nozzle which guides the arc-extinguishing gas pressurized in the compression chamber to an arc ignited at the first arc contactor,
• wherein:
• the insulation nozzle is formed integrally with the inner wall of the cylinder,
• the piston is driven by a columnar piston support inserted into an insertion hole provided in a support,
• the piston support includes a smaller diameter portion formed to have a smaller diameter in a part of the piston side formed into a columnar shape, and
• the arc-extinguishing gas flows out of a gap between the smaller diameter portion and the insertion hole, the gap being formed in the latter half of the current breaking action by driving the piston support.